Apparatus for forming the exterior wall of combustion chambers for rocket engines



May 5, 1970 K. BUTTER 3,510,063

APPARATUS FOR FORMING THE EXTERIOR WALL OF COMBUSTION CHAMBERS FOR ROCKET ENGINES Filed Sept. 1, 1967 INVENTOR Karl B utter ATTORNEYS United States Patent Ofiice 3,510,063 Patented May 5, 1970 int. Cl. B6415 33/06 U.S. Cl. 239-1271 6 Claims ABSTRACT OF THE DISCLOSURE The disclosure is directed ot a method of and apparatus for forming the exterior wall of a rocket engine combustion chamber including a thrust nozzle and having an interior wall defining a cylindrical section merging into a converging section connected by a reduced area throat to a diverging section, the interior wall having its exterior surface laterally subdivided into outwardly opening longitudinally extending coolant channels sealingly closed laterally by an exterior wall constituted by wire wound helically and continuously around the external surface of the internal wall and with adjacent convolutions sealingly secured to each other and to the interior wall.

In accordance with the disclosure, the starting end of the exterior wall is anchored at the throat, and the wire is then. wound helically around the interior wall in both axial directions outwardly from the throat along the diverging section and along the converging and cylindrical sections, whereafter the wire convolutions are sealingly interconnected to each other and ot the interior wall to sealingly close the coolant channels. For the anchoring of the starting end of the exterior wall at the throat, a two-part locking or anchoring collar is secured in embracing relation with the thoat and is formed to have the wire ends anchored thereto.

As the exterior wall is generally a two-layer winding, the locking or anchoring collar is provided with anchoring formations diametrically opposite each other, one formation being the starting point for the inner layer and the other formation being the starting point for the outer layer. Step and helical formations are provided on the locking and anchoring collar so that both the inner layer and the outer layer may be wound simultaneously around the combustion chamber with the convolutions of the outer layer smoothly overlying the convolutions of the inner layer.

Background of the invention A combustion chamber of the type to which the present method is applicable, and in which the exterior wall is formed by juxtaposed wire convolutions, is illustrated, for example, in US. Pat. No. 2,943,442 and US. Pat. No. 3,120,101. In these patents, the winding of the exterior wall around the interior wall of the combustion chamber is started at the upstream end of the combustion chamber, considered from the flow direction of the combustion gases. The manner of forming the exterior wall of the combustion chamber, as practiced hitherto, entails the hazard that the wire, when it is being wound in the area of the convergent section of the combustion chamber, tends to slide off in the direction of the combustion chamber throat, or toward the lesser diameter part of the combustion chamber. It thus cannot always be assured that the individual convolutions are in positive contact with each other, thus rendering problematical the absolutely required tightness of adjacent convolutions in contact with each other, as well as the rendering problematical perfect soldering, welding or adhesive bonding of adjacent convolutions of the exterior wall to each other.

Summary of the invention This invention realtes to a method of forming the exterior Wall of a combustion chamber having an interior wall defining a converging section connected to a diverging section and, more particularly, to an improved and simplified method of forming the exterior wall by winding wire helically around the exterior surface of the inner wall and in which positive contact between adjacent convolutions of the wound exterior wall is assured.

In accordance with the method of the invention, the above-mentioned disadvantages of prior art wound wire exterior walls for combustion chambers are avoided by beginning the winding by anchoring the starting end of the wall at the smallest diameter portion of the combustion chamber, as at the throat of the combustion chamber or its thrust nozzle. The wire is then wound helically around the interior Wall in both axial directions outwardly from the combustion chamber throat or the like, along the diverging section and along the converging and cylindrical sections.

For performing the invention method, an anchoring or locking collar is secured around the combustion chamber at the neck of the chamber, for fastening or anchoring the starting end or starting ends of one or more wire lengths. Beginning at the anchoring collar, one wire length, or a single wire in the case of a single layer winding, are wound around the converging section and the cylindrical section of the combustion chamber inner wall, and another Wire length, or single wire as the case may be, are Wound around the diverging section of the combustion chamber inner wall.

A feature of the invention is that appropriately shaped grooves for the insertion and anchoring of the starting ends of the wire lengths or wires are provided on the external peripheral surface of the locking or anchoring collar, which latter may expediently consist of two sections which can be clamped together around the neck of the combustion chamber. Preferably, the arrangement of the anchoring grooves and the wire lengths starting at the anchoring or holding collar is such that the various wire lengths run in the same peripheral or circumferential direction so that the combustion chamber exterior wall can be wound in a single operation.

As applied to the winding of a plural or multiple layer exterior wall including superposed convolutions of successive wire lengths, and particularly where the superposed convolutions may have different cross sections, the method of the invention assures complete covering of the winding buts or starting ends. This increases the strength of the completed exterior wall and improves the margin of safety with respect to tightness of the convolutions. For this purpose, preferably the anchoring or locking collar for the starting ends of the convolutions of the superposed Winding layers is stepped 01f in both axial directions relative to its outer peripheral surface, as viewed from its central diametric plane. Thereby, due to the developing axial staggering of the superposed convolutions, the two superposed windings extending in each axial direction from the holding or anchoring collar can be wound simultaneously.

The grooves for anchoring the starting ends of the various wire lengths, and provided on the exterior peripheral surface of the collar, can be arranged in a V-shape, with the apex of the V lying in the central diametric plane of the collar. More specifically, when two superposed windings are involved, the tWo grooves for fastening the starting ends of the wire lengths forming the inner layers form a V, and the two grooves for fastening the starting ends of the wire lengths forming the outer layers form another V. The two V-grooves are aligned, one behind the other, in a circumferential direction and are preferably diametrically opposite each other.

In addition to the advantages previously mentioned, the invention method creates, fundamentally, a prerequisite for faultless winding and thus a guarantee of the tightness of the combusion chamber exterior wall. In addition, the anchoring collar or locking collar facilitates assembly operations with respect to the formation of the exterior wall of the combustion chamber.

An object of the invention is to provide an improved method for forming the exterior wall of a combustion chamber having an interior wall defining a converging section connected by a reduced area throat to a diverging section.

Another object of the invention is to provide such a method in which tight contact between adjacent convolutions of a wire wound exterior wall is positively assured.

A further object of the invention is to provide such a method in which the winding of the exterior wall is started at the narrow throat of the combustion chamber and proceeds axially outwardly in both directions from the combustion chamber throat.

Still another object of the invention is to provide such a method of forming a wire wound exterior wall of a combustion chamber of the mentioned type in which the starting ends of the wire lengths are anchored to a collar embracing the combustion chamber at its narrow throat.

A further object of the invention is to provide such a method in which the anchoring collar is provided with grooves in its peripheral surface in which the starting ends of the wire lengths are anchored.

Still another object of the invention is to provide such a method in which the various wire lengths run in the same peripheral direction so that the combustion chamber exterior wall can be wound in a single operation.

A further object of the invention is to provide a method of the type just mentioned in which the winding buts or starting ends are completely enclosed to increase the strength of the exterior wall and improve the margin of safety with respect to tightness.

A further object of the invention is to provide a method as mentioned above in which, in the case of a multilayer winding, the successive superposed layers have their convolutions relatively staggered and are Wound simultaneously.

Another object of the invention is to provide such a method in which the various wire lengths have their starting ends anchored in novel formations in the anchoring collar and in which succeed each other circumferentially of the anchoring collar.

Brief description of the drawings For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a partial side elevation view, partially in longitudinal or axial section, of a combustion chamber to which the method of the invention is applied, the part of the figure not in section being illustrated without the exterior wall wound thereon; and

FIG. 2 is an end elevation view of means for anchoring the starting ends of the wire lengths.

Description of the preferred embodiment Referring to FIG. 1 of the drawing, the combustion chamber includes an interior wall having its exterior surface laterally subdivided into outwardly opening and longitudinally extending coolant channels 2 which are sealingly closed laterally by an exterior wall constituted by wire wound helically and continuously around the external surface of the interior wall and with adjacent convolutions sealingly secured to each other and to the interior wall 1. As will be apparent from FIG. 1, the exterior wall comprises two superposed layers of windings so arranged, in the illustrated example, that a total of four wire lengths are used. The four wire lengths include two Wire lengths 3a and 13a, extending in one axial direction of the combustion chamber, and two wire lengths 3b and 13b extending in the other axial direction of the combustion chamber. The wire lengths extend axially from the narrow throat or neck 4 of the combustion chamber, and have their starting ends anchored at the smallest diameter portion of the combustion chamber, namely at the combustion chamber throat 4. Starting from throat 4, the combustion chamber has a converging setcion 6 merging into a cylindrical section 7, and a diverging section 8, both the converging section and the diverging section merging relatively smoothly into the throat 4.

The wire end anchoring device 5 is in the form of a collar consisting of separable halves 9 and 10, as best seen in FIG. 2. The two halves 9 and 10 of the collar 5 are provided with opposing lugs 11 formed with apertures 12 to receive fastening or clamping screws or bolts when the two halves are placed in embracing relation with the throat 4 of the combustion chamber. The radially inner periphery 14 of collar 5 has a conforming fit with the exterior surface of the combustion chamber throat 4.

For the purpose of anchoring the starting ends of the wire lengths 3a, 3b and 13a, 13b, the exterior peripheral surface of anchoring collar or lock 5 is formed with a first pair of oblique grooves 15 and 16, and with a second pair of oblique grooves 17 and 18. The inner end 19 of each groove is expanded conically, and the respective wire lengths 3, 3b, 13a and 13b are likewise conically broadened or flattened at their starting ends 20. They are then conformingly clamped or wedged into the ends of the respective grooves 15 through 18.

Grooves 15 and 16 for securing the ends 20 of wire lengths 3a and 3b conjointly form a V whose apex is on the central diametric plane Qu of holding or anchoring lock or collar 5. Similarly, the two grooves 17 and 18 for anchoring the ends 20 of wire lengths 13a and 13b are formed into a second V whose apex lies in the central diametric plane Qu of holding lock or collar 5. Considered circumferentially of holding lock or collar 5, the two V-groove arrangements are aligned one behind the other.

As can be best seen in FIG. 1, each axial end surface of collar 5 is formed with a pair of diametrically opposite steps 21 and 22. The height of each step corresponds to the thickness of the wire lengths 3a and 3b, which lie on these steps. It is thereby possible, through the resultant axial staggering of the starting ends of the wire lengths for the inner and outer layers of the winding to wind both the inner and outer layers simultaneously.

In addition, the two end faces of holding lock or collar 5 are designed in a dual-start screw or thread fashion, in accordance with the pitch of the convolutions of the inner and outer winding layers. Thus, the axial extents of the shoulders 21 and 22 at the outlets of the respective grooves 15 through 18 correspond to the thickness of the respective winding layers. Thereby, the screw threads for the inner winding layers are staggered or offset in both an axial direction and a radial direction with respect to the screw threads for the outer winding layers.

In a manner known per se, lock or collar 5 and the wire lengths 3a, 3b, 13a and 1311 are vapor deposited with solder prior to winding, and the adjacent convolutions, both axially and radially of the combustion chamber, are united to each other and to the combustion chamber interior wall 1 by furnace soldering after completion of the winding of the exterior wall of the combustion chamber. Of course, instead of soldering the adjacent convolutions to each other and to the interior wall 1 of the combustion chamber, the exterior wall may be sealed by such methods as welding and adhesive bonding.

The converging section 6 and the diverging section 7, as well as the throat 5, form the thrust nozzles so that, in the illustrated example, the actual combustion chamber and the thrust nozzle are designed as a one-piece unit which has been generally referred to in the foregoing description as the combustion chamber.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. Apparatus for forming a multi-layer wire wound exterior wall of a combustion chamber having an interior wall defining a cylindrical section merging into a converging section connected by a reduced area throat to a diverging section, the interior wall having its exterior surface laterally subdivided into outwardly opening coolant channels sealingly closed by the exterior wall, said apparatus comprising a collar constructed to embrace said throat and having groves formed in its outer peripheral surface for inserting and anchoring the starting ends of the wire layers.

2. Apparatus for forming the exterior wall of a combustion chamber, as claimed in claim 1, in which said grooves are provided in the form of two pairs of grooves, each groove serving to anchor the end of a respective wire; the grooves of each pair intersecting in the form of a V whose apex is located in the central diametric plane of the collar, the two V-groove arrangements being located diametrically opposite each other and being aligned one behind the other in a direction circumferentially of the collar.

3. Apparatus for forming the exterior wall of a combustion chamber, as claimed in claim 2, in which each axial 6 end face of the collar is formed with an axially outwardly extending step serving to seat the starting portions of the wire of the inner layer, the steps having a height equal to the thickness of the wire forming the inner layer.

4. Apparatus for forming the exterior wall of a combustion chamber, as claimed in claim 3, in which the axial end surfaces of the collar are formed with second shoulders each extending axially outwardly and each stepped radially from the first mentioned shoulders by the thickness of the wire forming the inner layer, each of the shoulders being at the outlet end of a respective groove and being arranged in the form of a dual-start thread corresponding to the respective pitches of the convolutions of the inner and outer winding layers; whereby the convolutions of the inner winding layer are staggered axially and radially with respect to the convolutions of the outer winding layer.

5. Apparatus for forming the exterior wall of a combustion chamber, as claimed in claim 1, in which said collar comprises two semi cylindrical sections conjointly embracing said throat.

6. Apparatus for forming the exterior wall of a combustion chamber, as claimed in claim 1, in which the radially inner surface of the collar is formed to conformingly engage the radially outer surface of the combustion chamber throat.

References Cited UNITED STATES PATENTS 2,976,679 3/ 1961 Dalgleish.

3,044,257 7/ 1962 Knapp.

3,162,012 12/1964 Blaze et al.

3,224,678 12/ 1965 Rosrnan.

3,289,943 12/1966 Thomas et a1 239-127.1

EVERETT W. KIRBY, Primary Examiner US. Cl. X.R. 

